Rotary internal combustion engine

ABSTRACT

A rotary engine for two cycle operation having arcuate combustion chambers formed in a rotor and correspondingly arcuate pistons mounted for swinging reciprocation in the combustion chambers on connecting rods pivoted to the rotor. The housing contains the rotor and provides an oblong inner periphery forming a raceway for cam followers mounted on the pistons so that, when ignition of the fuel mixture occurs at the beginning of a power stroke, the pistons are forced outwardly against the relative incline of the raceway in such a manner as to cause the pistons to impart rotary motion to the rotor. At about the end of the power stroke, the movement of the rotor causes recesses formed in the rotor at the inner end of the combustion chamber to communicate with exhaust and intake ports formed in the housing on opposite sides of the rotor for venting the spent gasses through one of the recesses and receiving a fresh charge of fuel mixture under pressure through the other recess in a scavenging fashion. The momentum of the rotor tends to cause it to rotate through the compression cycle wherein the cam followers riding on the raceway force the pistons into the combustion chambers to compress the air-gas mixture for ignition at approximately the innermost retracted position and thus initiate the next power stroke.

United States Patent [191 Blackwood ROTARY INTERNAL COMBUSTION ENGINE[76] Inventor: William A. Blackwood, 295 Polaris Ave., Mountain View,Calif. 94040 [22] Filed: Aug. 16, 1973 [21] Appl. No.: 388,985

[52] US. Cl. 123/43 C; 123/44 C, 123/44 D [51] Int. F02]! 57/00; F02B57/04 [58] Field of Search... 123/43 C, 44 C, 44E, 44 D;

[56] References Cited UNITED STATES PATENTS Primary Examiner-John J.Vrablik Attorney, Agent, or F irmSchapp and Hatch 1 1 ABSTRACT A rotaryengine for two cycle operation having arcu- 51 Dec.23, 1975 atecombustion chambers formed in a rotor and correspondingly arcuatepistons mounted for swinging reciprocation in the combustion chambers onconnecting rods pivoted to the rotor. The housing contains the rotor andprovides an oblong inner periphery forming a raceway for cam followersmounted on the pistons so that, when ignition of the fuel mixture occursat the beginning of a power stroke, the pistons are forced outwardlyagainst the relative incline of the raceway in such a manner as to causethe pistons to impart rotary motion to the rotor. At about the end ofthe power stroke, the movement of the rotor causes recesses formed inthe rotor at the inner end of the combustion chamber to communicate withexhaust and intake ports formed in the housing on opposite sides of therotor for venting the spent gasses through one of the recesses andreceiving a fresh charge of fuel mixture under pressure through theother recess in a scavenging fashion. The momentum of the rotor tends tocause it to rotate through the compression cycle wherein the camfollowers riding on the raceway force the pistons into the combustionchambers to compress the air-gas mixture for ignition at approximatelythe innermost retracted position and thus initiate the next powerstroke.

38 Claims, 9 Drawing Figures US. Patent Dec. 23, 1975 Sheet 1 of43,927,647

U.S. Patent Dec. 23, 1975 Sheet 2 of4 3,927,647

PIE- .4.

U.S. Patcent Dec. 23, 1975 Sheet 4 of4 3,927,647

ROTARY INTERNAL COMBUSTION ENGINE BACKGROUND OF THE INVENTION Thepresent invention relates to a ROTARY EN- GINE and more particularly toa two cycle internal combustion rotary engine with pivotally swingablepis- 00118.

Prior art internal combustion engines typically have a plurality ofpistons each mounted in a separate cylindrical combustion chamber inparallel alignment. Each piston has a separate piston rod connectedthereto and the piston rods are connected through a crankshaft and trainof gears to impart rotational energy. These devices generate asubstantial amount of friction and consume excessive power for variousother reasons.

Rotary engines have been therefore relied upon to reduce friction andthereby increase efficiency. They can be made lightweight and compactand have desirable power-to-weight ratios. Furthermore, they arecharacteristically simple to cast and fabricate.

Rotary engines have been developed which act against a single cam trackto convert lineal reciprocating motion of pistons mounted in combustionchambers formed on a rotor to rotary motion of the rotor. US. Pat. No.2,439,150 to Smith is typical of such devices. The combustion chambersand pistons in these engines are uniformly cylindrical in shape. As therotor rotates, the reciprocal movement of the piston and connectingpiston rod imparts an undesirable lateral cocking moment on the pistonsliding against the cylindrical wall as the followers move on therelative incline of the cam surface. This moment causes unbalancedstresses between the piston and cylindrical chamber wall and increasesfriction between them. This friction results in a reduction inefficiency of the engine and excessive stress and wear on the materialsof the piston and cylinder wall.

SUMMARY OF THE INVENTION The general purpose of the present invention isto provide an improved rotary engine in which the rotor is mounted in ahousing providing a cam surface having an oblong or generally ellipticalinner periphery. The engine has arcuate combustion chambers formed inthe rotor and arcuate pistons each mounted for swinging reciprocation inone of the chambers on a connecting rod pivoted to the rotor. Eachpiston is formed in mating configuration with the associated combustionchamber. The arcuate shape of the pistons and combustion chambers andthe pivoted connecting rods eliminates the lateral bending and torqueforces inherent in prior rotary engines having cylindrical pistons andcombustion chambers. These factors further reduce the friction betweenthe pistons and combustion chambers to thereby increase efficiency.

Cam rollers or followers are mounted on each piston so that when apiston is retracted inwardly at the beginning of a power stroke, asignition of the fuel mixture occurs in the associated combustionchamber, the piston is forced outwardly against the oblong cam surfaceto cause the piston to impart rotary motion to the rotor. The piston isalso urged outwardly by centrifugal force as the rotor rotates duringthe power stroke.

Each combustion chamber has its end relieved to form a pair of recessesseparated by a protuberance. Approximately at the end of the powerstroke, the combustion chamber communicates with exhaust and intakeports formed in the housing sidewalls on opposite sides of the rotor toexhaust the spent gases through one of the recesses and receive a chargeof the fuel mixture into the chamber through the other recess, in ascavenging fashion. The exhaust port is positioned so that it comes intocommunication with the combustion chamber slightly before the intakeport for improved scavenging. The cam surface is formed to accommodatethe burn characteristics of the particular fuel mixture.

The angular momentum of the rotor tends to cause it to continue torotate through the compression cycle. In this cycle, each cam followerbeing mounted on a piston head, travels up the relative incline of thecam surface and forces the piston to swing into the inward retractedposition, compressing the fuel mixture. Ignition occurs when the pistonis at approximately the innermost retracted position, beginning thepower stroke once more. The rotation of the rotor at the beginning ofthe power stroke has been augmented by centripetal force due to theradially inward retraction of the pistons into the combustion chambersat the end of the compression stroke.

In one form, the engine is cooled by air cooling fins mounted on therotor. The air passed through the air cooling fins as well as blowby andexhaust gases may be vented to an afterburner which burns this mixtureof gases. The burnt gases may be used to drive a turbine to impartrotational energy to a blower to blow air onto the fins.

Accordingly, an object of the present invention is to provide a rotaryengine with pivotally swingable pistons.

Another object of the present invention is to provide rotary enginemeans having at least one arcuate combustion chamber and at least onearcuate piston formed in mating configuration.

A further object of the present invention is to provide a housing for arotary engine having an elliptical or oblong inner periphery providing acam surface shaped for accommodating the burn characteristics of anairgas fuel mixture ignited in the combustion chambers.

Still another object of the present invention is to provide an intakeand an exhaust port each positioned on sealing plates on opposite sidesof a rotary engine and aligned slightly askew relative to each other forimproved scavenging.

Yet another object of the present invention is the provision of a pairof recesses separated by a wall in a combustion chamber of a rotaryengine for communicating with exhaust and intake ports for improvedscavenging.

An additional object of the present invention is to provide fins mountedon the periphery of a rotary engine for cooling thereof.

Further objects and advantages of the present invention will becomeapparent as the specification proceeds, and the new useful features willbe fully defined in the claims appended hereto.

BRIEF DESCRIPTION OF THE DRAWINGS The preferred form of the presentinvention is illustrated in the accompanying drawings, in which,

FIG. 1, is a side elevational view of a rotary engine constructed inaccordance with the present invention, with portions removed to showinternal mechanism;

FIG. 2, is a side elevational view on a reduced scale of the engine ofFIG. 1 at a different point in its operat- 3 ing cycle;

FIG. 3, is a view similar to that of FIG. 2 but at another point in itsoperating cycle;

FIG. 4, is a cross-sectional view taken along the plane of line 44 ofFIG. 2;

FIG. 5, is a cross-sectional view taken along the plane of line 5-5 ofFIG. 4;

FIG. 6, is a cross-sectional view taken along the plane of line 6-6 ofFIG. 1;

FIG. 7, is a cross-sectional view taken along the plane of line 77 ofFIG. 3;

FIG. 8, is a partially exploded perspective view of the rotor andpistons of the rotary engine of the present invention; and

FIG. 9, is a schematic diagram of a carburetion and exhaust system forthe engine of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, there isshown a rotor 11 having arcuate pistons 12 and 13 mounted thereon forreciprocal curvilinear movement in arcuate combustion chambers 14 and 16respectively. The rotor is mounted on a central drive shaft 17 fortransmitting rotational energy from the movement of the rotor 11 to aload. The rotor and piston assembly is mounted in a housing 18 having anoblong or elliptical inner peripheral surface 19. The pistons 12 and 13are connected to connecting rods 21 and 22 respectively, and theconnecting rod and piston assemblies have rollers 23 and 24 respectivelyformed for following the contour of the cam surface or raceway providedby inner periphery 19. The profile of the cam surface 19 may be modifiedto accommodate the burn characteristics of the particular fuel mixturebeing used. The connecting rods 21 and 22 are journalled for swingingmovement on pivot pins 26 and 27, respectively, carried by rotor 11shown in FIG. 8.

The arcuate combustion chambers 14 and 16 have seals 28 as shown forslidably sealing the pistons 12 and 13 in the chambers. The combustionchambers are further sealed on the sides by end plates 29 and 31 eachsecured on opposite sides of the rotor 11 by screws as shown in FIG. 4.Side plates and 30 are stationary with the housing and reduce thetolerances between the end plates and the housing. The side plates 25and 30 have ports and respectively formed thereon. The end plate 29 hasintake ports 33 as shown in dotted lines in FIG. 5 and the end plate 31has exhaust ports 32 shown in solid lines in FIG. 5. The exhaust ports32 are slightly misaligned from the intake ports 33 on the oppositefaces to permit a combustion chamber to communicate with the exhaustports slightly before communication with the intake ports. This permitsthe venting of the exhaust gas out of the combustion chamber to beginslightly before the beginning of the injection of the fresh fuel mixturethrough the intake port and into the chamber to improve scavenging.

As shown in FIGS. 4 and 7, the interior end of the combustion chamber 14is relieved to provide an intake recess 43 and an exhaust recess 48separated by a protuberance 46. Similarly, the interior end of thecombustion chamber 16 is also relieved to provide an intake recess 44and an exhaust recess 49 separated by a protuberance 47. As shown inFIG. 8, the head of each of the pistons 12 and 13 is formed in matingconfiguration with the associated ends of the combustion chambers 14 and16 to accommodate the described recesses and protuberances.

As may best be seen in FIG. 4, air is here injected under pressurethrough passages 34 and fuel is introduced through fuel injectors 36 and37 to form a fuel mixture which is forced into the combustion chambersthrough ports 35 in side plate 25, intake ports 33 and recesses 43 and44. The fuel mixture in the combustion chambers is compressed during thecompression stroke of the pistons which begins approximately when thepistons are at their outermost position as shown in FIG. 2. As the rotorrotates in the clockwise direction, the fuel mixture is compressed bythe forcing inwardly of the pistons 12 and 13 into combustion chambers14 and 16 respectively as the rollers 23 and 24 are deflected inwardlyby cam surface 19. The retraction of the pistons toward the center ofgravity of the rotor during the compression stroke generates acentripetal force to enhance the rotation of the rotor 11.

When the pistons are approximately at their completely retractedposition, as shown in FIG. 3, the power stroke is begun through ignitionof the compressed mixture of air and fuel by spark plugs 38, 39, 41 and42 as shown in FIG. 7. The ignition and combustion of the compressedfuel-air mixture causes pressure to be exerted against the pistons 12and 13 to urge them outwardly. The rollers 23 and 24 mounted on pistons12 and 13 respectively follow the cam surface 19 from the short diagonalat about the beginning of the power stroke, shown in FIG. 3, to thepoints on the profile surface intersecting the long diagonal. Thecentrifugal force urging the pistons outwardly as well as the inertia ofthe rotor 11 and the shaft 17, cause the rotor and shaft to rotatethrough the next compression stroke to thereby begin the venting of theexhaust gas through recesses 48 and 49, exhaust ports 32 and ports 40 onside plate 30. Shortly thereafter, the venting of an airgas mixture isbegun through intake ports 33 to begin the compression stroke once more.The recesses and protuberances cause a circulation path as shown by thearrows in FIG. 4 to improve scavenging action.

The engine here is shown as being cooled by rotor mounted fins 51 whichare shown in greater detail in FIGS. 1 and 6. The fins 51 conduct airthrough suitable apertures 62 in the housing. A suitable shroud ormanifold (not shown) is mounted on the back side of the housing to ductthe air blown through the housing into an exhaust system (not shown).

In the carburetion and exhaust system shown schematically in FIG. 9, ablower 61 draws air through a carburetor 63 and propels the fuel-airmixture into the chambers for combustion. The exhaust gases are passedthrough line 66 and vented to a suitable afterburner 67. The mixture ofexhaust gases are burned further in the afterburner 67. Energy from suchcombustion is imparted to a turbine 68 to drive the blower 61 through asuitable coupling 69.

The arcuate shape of the pistons and combustion chambers permit theengine to operate without severe stresses in the piston and rotormaterials caused by misalignment of force trying to cock and bend thepistons in the cylinders, and the resulting reduction in frictionimproves efficiency. The rotor is preferably constructed of aluminum andthe pistons are preferably formed of steel. This provides for bettercooling of the rotor. The seals may be better placed in the rotor whenformed of aluminum, and the pivoted construction of the piston assemblypermits the use in the rotor of relatively soft, high heat dissipatingmetal such as aluminum.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. For example, the mass ofthe rotor 11 could be reduced by cutting out portions of the rotor whichdo not communicate with the combustion chambers 14 and 16, the exhaustports 32 or the intake port 33. Furthermore, although the preferredembodiment is constructed with two combustion chambers and pistons, theengine may be constructed with any number of combustion chambers toaccommodate any desired utilization thereof.

Of course, it will be appreciated that more than one rotor assembly maybe mounted on a single shaft with the cylinders of one rotor preferablyoriented in angularly spaced relation to the others for multiplying thenumber of impulses delivered to the shaft.

The rotary engine of the present invention also is suitable forfour-cycle mode of operation with relocation of the valve openings. Therotor and swinging piston structure may be adapted for use in a steam orfluid driven engine. it is therefore to be understood that within thescope of the appended claims, the invention may be practiced otherwisethan as specifically described.

l claim:

I. A rotary engine for two-cycle operation comprisa housing formed toprovide an oblong inner cam surface,

a rotor carried for relative rotation in said housing,

walls in said rotor defining at least one arcuate combustion chamber,

a correspondingly arcuate piston mounted for curvilinear reciprocationin said combustion chamber inwardly toward the axis of rotation of saidrotor and outwardly toward said cam surface such that the centerline ofsaid chamber, if extended, would pass through the axis of said rotor,

and follower means for operatively connecting said piston to said oblonginner cam surface,

whereby said arcuate piston is urged outwardly to travel along saidoblong inner cam surface and impart rotation to said rotor by combustionin said arcuate combustion chamber to provide the power stroke and isurged inwardly by travel along said inner cam surface to provide thecompression stroke.

2. A rotary engine as described in claim 1 and further comprising meansfor injecting a mixture of air and fuel into said arcuate combustionchamber.

3. A rotary engine as described in claim 1 and wherein said oblong camsurface of said housing is shaped to accommodate the burncharacteristics of the fuel-air mixture in said arcuate combustionchamber.

4. The rotary engine as described in claim 1 and further comprising atleast one seal circumferentially formed around the sides of said arcuatecombustion chamber for slidably sealing said piston in said arcuatecombustion chamber.

5. A rotary engine as described in claim 1 and further comprising anintake port formed on one side of said housing for communicating withsaid arcuate combustion chamber, and an exhaust port formed on theopposite side of said housing positioned slightly askew from said intakeport for communicating with said combustion chamber to thereby improvescavenging in said combustion chamber.

6. A rotary engine as described in claim 5 and wherein said exhaust portis positioned for commencing communication with said arcuate combustionchamber prior to the commencement of communica tion between said arcuatecombustion chamber and said intake port.

7. A rotary engine as described in claim 6 and wherein the internal endof said arcuate combustion chamber is relieved to provide a pair ofrecesses with one formed to communicate with said intake port and thesecond formed for communication with said exhaust port.

8. A rotary engine as described in claim 7 and wherein said arcuatecombustion chamber is further formed with a protuberance separating saidpair of recesses.

9. A rotary engine as described in claim 1 and further comprising aplurality of fins mounted on said rotor for deflecting air to cool therotary engine.

10. A rotary engine as described in claim 9 and fur ther comprisingventing means for venting blowby and exhaust gases.

1]. A rotary engine as described in claim 1 and further comprising aplurality of arcuate combustion chambers formed in said rotor and aplurality of arcuate pistons each mounted in one of said combustionchambers and communicating with said oblong inner cam surface.

12. A rotary engine as described in claim 11 and further comprising aplurality of intake ports formed on one side of said housing forcommunicating with said plurality of combustion chambers and an equalnumber of exhaust ports each formed on the opposite side of said housingand each positioned slightly askew from one of said intake ports forcommunicating with said plurality of combustion chambers to therebyimprove scavenging in said plurality of combustion chambers.

13. A rotary engine as described in claim 12 and wherein each of saidplurality of said exhaust ports is positioned for commencingcommunication with one of said plurality of arcuate combustion chambersprior to the commencement of communication between said one of saidplurality of arcuate combustion chambers and the associated intake portof said plurality of intake ports on the opposite side of said housing.

14. A rotary engine as described in claim 13 and wherein each of saidarcuate combustion chambers is formed with a pair of recesses with oneformed to communicate with said plurality of intake ports and the secondformed for communication with said plurality of exhaust ports.

15. A rotary engine as described in claim 14 and wherein each of saidplurality of arcuate combustion chambers is formed with a protuberanceseparating said pair of recesses formed therein.

16. A rotary engine as described in claim 15 and wherein the head ofeach of said plurality of arcuate pistons is formed in matingconfiguration with the inner end of the associated combustion chamber.

17. A rotary engine as described in claim 16 in which said rotor isformed of aluminum.

18. A rotary engine as described in claim 17 in which said plurality ofarcuate pistons are formed of steel.

19. The rotary engine as described in claim 1 and further comprising aconnecting rod rigidly mounted on said piston and pivotally connected tosaid rotor so as to prevent cocking action of said piston in saidcombustion chamber.

20. The rotary engine as described in claim 19 and wherein said followermeans is mounted on said connecting rod.

21. The rotary engine as described in claim 20 and wherein saidconnecting rod is arcuate in shape.

22. A rotary engine, comprising a housing having circumferential and endwalls defining an enclosure providing an oblong inner cam surface on itsinner periphery,

a rotor carried in said enclosure for rotation relative to said housing,

said rotor being formed to provide a combustion chamber having a headend near the axis of rotation of said rotor and curving along a circulararc from such head end outwardly to the outer periphery of said rotorsuch that extension of the center line are of the chamber passes throughthe axis of rotation,

a correspondingly arcuate piston slidably mounted in said combustionchamber for reciprocation therein toward and away from said head end,

and follower means for operatively connecting said piston to said oblonginner cam surface,

whereby said arcuate piston is urged outwardly to travel along saidoblong inner cam surface and impart rotation to said rotor by combustionin said arcuate combustion chamber to provide the power stroke and isurged inwardly by travel along said inner cam surface to provide thecompression stroke.

23. A rotary engine as described in claim 22 and wherein said piston isswingably mounted for arcuate movement corresponding to the shape ofsaid combustion chamber about a pivot point stationary with respect tosaid rotor.

24. A rotary engine as described in claim 22 and wherein a plurality ofsaid combustion chambers are formed in equidistant circumferentiallyspaced relation in said rotor, and a plurality of said pistons areslidably mounted in said combustion chambers.

25. A rotary engine as described in claim 22 and wherein a control armis journaled on said rotor for swinging movement of its distal end in anarc corresponding to the arc of said combustion chamber, said pistonbeing rigidly mounted on said distal end of said control arm wherebycocking of said piston with respect to said combustion chamber isprecluded.

26. A rotary engine as described in claim 25 and wherein said followermeans comprises a cam roller journaled on said distal end of saidcontrol arm.

27. A rotary engine as described in claim 22 and further comprising anintake port formed through one of said end walls in position forcommunicating with said combustion chamber at specific angular positionsof said rotor, and an exhaust port formed through the other of said endwalls in position for communicating with said combustion chamber atspecific angular positions of said rotor.

28. A rotary engine as described in claim 27 and wherein said intakeport is positioned slightly circumferentially askew from said exhaustport for improving scavenging from said combustion chamber.

29. A rotary engine as described in claim 28 and wherein the internalend of said arcuate combustion chamber is relieved to provide a pair ofrecesses with one formed to communicate with said intake port and thesecond formed for communication with said exhaust port.

30. A rotary engine as described in claim 29 and wherein said arcuatecombustion chamber is further formed with a protuberance separating saidpair of recesses.

31. A rotary engine for two-cycle operation compris ing, a housingformed to provide an oblong inner cam surface, a rotor carried forrelative rotation in said housing,

walls in said rotor defining a plurality of arcuate combustion chambers,plurality of arcuate pistons each mounted in one of said combustionchambers for curvilinear reciprocation in said combustion chambersinwardly toward the axis of rotation of said rotor and outwardly towardsaid cam surfaces, each communicating with said oblong inner camsurface.

a plurality of intake ports formed on one side of said housing forcommunicating with said plurality of combustion chambers and an equalnumber of exhaust ports each formed on the opposite side of said housingand each positioned slightly askew from one of said intake ports forcommunicating with said plurality of combustion chambers to therebyimprove scavenging in said plurality of combustion chambers,

each of said plurality of said exhaust ports being positioned forcommencing communication with one of said plurality of arcuatecombustion chambers prior to the commencement of communication betweensaid one of said plurality of arcuate combustion chambers and theassociated intake port of said plurality of intake ports on the oppositeside of said housing,

each of said arcuate combustion chambers being formed with a pair ofrecesses with one formed to communicate with said plurality of intakeports and the second formed for communication with said plurality ofexhaust ports,

each of said plurality of arcuate combustion chambers having aprotuberance separating said pair of recesses formed therein, and

follower means for operatively connecting said pistons to said oblonginner cam surface,

whereby said arcuate pistons are urged outwardly to travel along saidoblong inner cam surface and impart rotation to said rotor by combustionin said arcuate combustion chambers to provide the power stroke and areurged inwardly by travel along said inner cam surface to provide thecompression stroke.

32. A rotary engine as described in claim 31 and wherein the head ofeach of said plurality of arcuate pistons is formed in matingconfiguration with the inner end of the associated combustion chamber.

33. A rotary engine as described in claim 32 in which said rotor isformed of aluminum.

34. A rotary engine as described in claim 33 in which said plurality ofarcuate pistons are formed of steel.

35. A rotary engine for two-cycle operation comprising, a housing formedto provide an oblong inner cam surface, a rotor carried for relativerotation in said housing,

walls in said rotor defining at least one combustion chamber ofrectangular cross-section opening to the periphery of said rotor andextending into said rotor along an arcuate path having as its center ofcurvature a point on said rotor circumferentially spaced from saidcombustion chamber, the centerline of said path extended passing throughthe axis of said rotor,

a correspondingly arcuate piston mounted for curvilinear reciprocationin said combustion chamber inwardly toward the axis of rotation of saidrotor and outwardly toward said cam surface,

an arm rigidly secured to the outer end of said piston and journalled tosaid rotor for swinging movement on one axis coinciding with the centerof curvature of said combustion chamber,

and, a cam follower journalled on said arm adjacent to said outer end ofsaid piston in position to track along said cam surface,

whereby said arcuate piston is urged outwardly to travel along saidoblong inner cam surface and impart rotation to said rotor by combustionin said arcuate combustion chamber to provide the power stroke and isurged inwardly by travel along said inner cam surface to provide thecompression stroke.

36. A rotary engine as described in claim 35 and wherein a plurality ofsaid combustion chambers are formed in equally circumferentially spacedrelation in said rotor, and a piston and arm and cam follower areprovided for each of said combustion chambers.

37. A rotary engine for two-cycle operation comprising, a housing formedto provide an oblong inner cam surface, a rotor carried for relativerotation in said housing,

walls in said rotor defining at least one arcuate combustion chamber,

a correspondingly arcuate piston mounted for curvilinear reciprocationin said combustion chamber inwardly toward the axis of rotation of saidrotor and outwardly toward said cam surface,

and follower means for operatively connecting said piston to said oblonginner cam surface,

an intake port formed on one side of said housing for communicating withsaid arcuate combustion chamber,

an exhaust port formed on the opposite side of said housing positionedslightly askew from said intake port for communicating with saidcombustion chamber to thereby improve scavenging in said combustionchamber, said exhaust port being positioned for commencing communicationwith said arcuate combustion chamber prior to the commencement ofcommunication between said arcuate combustion chamber and said intakeport, and,

the internal end of said arcuate combustion chamber being relieved toprovide a pair of recesses with one formed to communicate with saidintake port 10 and the second formed for communication with said exhaustport and having a protuberance separating said pair of recesses,

whereby said arcuate piston is urged outwardly to travel along saidoblong inner cam surface and impart rotation to said rotor by combustionin said arcuate combustion chamber to provide the power stroke and isurged inwardly by travel along said inner cam surface to provide thecompression stroke.

38. A rotary engine, comprising a housing having circumferential and endwalls defining an enclosure providing an oblong inner cam surface on itsinner periphery,

a rotor carried in said enclosure for rotation relative to said housing,

said rotor being formed to provide a combustion chamber having a headend near the axis of rotation of said rotor and curving along a circularare from such head end outwardly to the outer periphery of said rotor,

a correspondingly arcuate piston slidably mounted in said combustionchamber for reciprocation therein toward and away from said head end,

follower means for operatively connecting said piston to said oblonginner cam surface,

said housing end walls being parallel, said rotor being slidably mountedbetween said end walls,

an intake port formed through one of said end walls in position forcommunicating with said combustion chamber at specific angular positionsof said rotor, and an exhaust port formed through the other of said endwalls in position for communicating with said combustion chamber atspecific angular positions of said rotor,

said intake port being positioned slightly circumferentially askew fromsaid exhaust port for improving scavenging from said combustion chamber,and,

the internal end of said arcuate combustion chamber being relieved toprovide a pair of recesses with one formed to communicate with saidintake port and the second formed for communication with said exhaustport, said arcuate combustion chamber having a protuberance separatingsaid pair of recesses,

whereby said arcuate piston is urged outwardly to travel along saidoblong inner cam surface and impart rotation to said rotor by combustionin said arcuate combustion chamber to provide the power stroke and isurged inwardly by travel along said inner cam surface to provide thecompression

1. A rotary engine for two-cycle operation comprising, a housing formedto provide an oblong inner cam surface, a rotor carried for relativerotation in said housing, walls in said rotor defining at least onearcuate combustion chamber, a correspondingly arcuate piston mounted forcurvilinear reciprocation in said combustion chamber inwardly toward theaxis of rotation of said rotor and outwardly toward said cam surfacesuch that the centerline of said chamber, if extended, would passthrough the axis of said rotor, and follower means for operativelyconnecting said piston to said oblong inner cam surface, whereby saidarcuate piston is urged outwardly to travel along said oblong inner camsurface and impart rotation to said rotor by combustion in said arcuatecombustion chamber to provide the power stroke and is urged inwardly bytravel along said inner cam surface to provide the compression stroke.2. A rotary engine as described in claim 1 and further comprising meansfor injecting a mixture of air and fuel into said arcuate combustionchamber.
 3. A rotary engine as described in claim 1 and wherein saidoblong cam surface of said housing is shaped to accommodate the burncharacteristics of the fuel-air mixture in said arcuate combustionchamber.
 4. The rotary engine as described in claim 1 and furthercomprising at least one seal circumferentially formed around the sidesof said arcuate combustion chamber for slidably sealing said piston insaid arcuate combustion chamber.
 5. A rotary engine as described inclaim 1 and further comprising an intake port formed on one side of saidhousing for communicating with said arcuate combustion chamber, and anexhaust port formed on the opposite side of said housing positionedslightly askew from said intake port for communicating with saidcombustion chamber to thereby improve scavenging in said combustionchamber.
 6. A rotary engine as described in claim 5 and wherein saidexhaust port is positioned for commencing communication with saidarcuate combustion chamber prior to the commencement of communicationbetween said arcuate combustion chamber and said intake port.
 7. Arotary engine as described in claim 6 and wherein the internal end ofsaid arcuate combustion chamber is relieved to provide a pair ofrecesses with one formed to communicate with said intake port and thesecond formed for communication with said exhaust port.
 8. A rotaryengine as described in claim 7 and wherein said arcuate combustionchamber is further formed with a protuberance separating said pair ofrecesses.
 9. A rotary engine as described in claim 1 and furthercomprising a plurality of fins mounted on said rotor for deflecting airto cool the rotary engine.
 10. A rotary engine as described in claim 9and further comprising venting means for venting blowby and exhaustgases.
 11. A rotary engine as described in claim 1 and furthercomprising a plurality of arcuate combustion chambers formed in saidrotor and a plurality of arcuate pistons each mounted in one of saidcombustion chambers and communicating with said oblong inner camsurface.
 12. A rotary engine as described in claim 11 and furthercomprising a plurality of intake ports formed on one side of saidhousing for communicating with said plurality of combustion chambers andan equal number of exhaust ports each formed on the opposite side ofsaid housing and each positioned slightly askew from one of said intakeports for communicating with said plurality of combustion chambers tothereby improve scavenging in said plurality of combustion chambers. 13.A rotary engine as described in claim 12 and wherein each of saidplurality of said exhaust ports is positioned for commencingcommunication with one of said plurality of arcuate combustion chambersprior to the commencement of communication between said one of saidplurality of arcuate combustion chambers and the associated intake portof said plurality of intake ports on the opposite side of said housing.14. A rotary engine as described in claim 13 and wherein each of saidarcuate combustion chambers is formed with a pair of recesses with oneformed to communicate with said plurality of intake ports and the secondformed for communication with said plurality of exhaust ports.
 15. Arotary engine as described in claim 14 and wherein each of saidplurality of arcuate combustion chambers is formed with a protuberanceseparating said pair of recesses formed therein.
 16. A rotary engine asdescribed in claim 15 and wherein the head of each of said plurality ofarcuate pistons is formed in mating configuration with the inner end ofthe associated combustion chamber.
 17. A rotary engine as described inclaim 16 in which said rotor is formed of aluminum.
 18. A rotary engineas described in claim 17 in which said plurality of arcuate pistons areformed of steel.
 19. The rotary engine as described in claim 1 andfurther comprising a connecting rod rigidly mounted on said piston andpivotally connected to said rotor so as to prevent cocking action ofsaid piston in said combustion chamber.
 20. The rotary engine asdescribed in claim 19 and wherein said follower means is mounted on saidconnecting rod.
 21. The rotary engine as described in claim 20 andwherein said connecting rod is arcuate in shape.
 22. A rotary engine,comprising a housing having circumferential and end walls defining anenclosure providing an oblong inner cam surface on its inner periphery,a rotor carried in said enclosure for rotation relative to said housing,said rotor being formed to provide a combustion chamber having a headend near the axis of rotation of said rotor and curving along a circulararc from such head end outwardly to the outer periphery of said rotorsuch that extension of the center line arc of the chamber passes throughthe axis of rotation, a correspondingly arcuate piston slidably mountedin said combustion chamber for reciprocation therein toward and awayfrom said head end, and follower means for operatively connecting saidpiston to said oblong inner cam surface, whereby said arcuate piston isurged outwardly to travel along said oblong inner cam surface and impartrotation to said rotor by combustion in said arcuate combustion chamberto provide the power stroke and is urged inwardly by travel along saidinner cam surface to provide the compression stroke.
 23. A rotary engineas described in claim 22 and wherein said piston is swingably mountedfor arcuate movement corresponding to the shape of said combustionchamber about a pivot point stationary with respect to said rotor.
 24. Arotary engine as described in claim 22 and wherein a plurality of saidcombustion chambers are formed in equidistant circumferentially spacedrelation in said rotor, and a plurality of said pistons are slidablymounted in said combustion chambers.
 25. A rotary engine as described inclaim 22 and wherein a control arm is journaled on said rotor forswinging movement of its distal end in an arc corresponding to the arcof said combustion chamber, said piston being rigidly mounted on saiddistal end of said control arm whereby cocking of said piston withrespect to said combustion chamber is precluded.
 26. A rotary engine asdescribed in claim 25 and wherein said follower means compriSes a camroller journaled on said distal end of said control arm.
 27. A rotaryengine as described in claim 22 and further comprising an intake portformed through one of said end walls in position for communicating withsaid combustion chamber at specific angular positions of said rotor, andan exhaust port formed through the other of said end walls in positionfor communicating with said combustion chamber at specific angularpositions of said rotor.
 28. A rotary engine as described in claim 27and wherein said intake port is positioned slightly circumferentiallyaskew from said exhaust port for improving scavenging from saidcombustion chamber.
 29. A rotary engine as described in claim 28 andwherein the internal end of said arcuate combustion chamber is relievedto provide a pair of recesses with one formed to communicate with saidintake port and the second formed for communication with said exhaustport.
 30. A rotary engine as described in claim 29 and wherein saidarcuate combustion chamber is further formed with a protuberanceseparating said pair of recesses.
 31. A rotary engine for two-cycleoperation comprising, a housing formed to provide an oblong inner camsurface, a rotor carried for relative rotation in said housing, walls insaid rotor defining a plurality of arcuate combustion chambers, aplurality of arcuate pistons each mounted in one of said combustionchambers for curvilinear reciprocation in said combustion chambersinwardly toward the axis of rotation of said rotor and outwardly towardsaid cam surfaces, each communicating with said oblong inner camsurface. a plurality of intake ports formed on one side of said housingfor communicating with said plurality of combustion chambers and anequal number of exhaust ports each formed on the opposite side of saidhousing and each positioned slightly askew from one of said intake portsfor communicating with said plurality of combustion chambers to therebyimprove scavenging in said plurality of combustion chambers, each ofsaid plurality of said exhaust ports being positioned for commencingcommunication with one of said plurality of arcuate combustion chambersprior to the commencement of communication between said one of saidplurality of arcuate combustion chambers and the associated intake portof said plurality of intake ports on the opposite side of said housing,each of said arcuate combustion chambers being formed with a pair ofrecesses with one formed to communicate with said plurality of intakeports and the second formed for communication with said plurality ofexhaust ports, each of said plurality of arcuate combustion chambershaving a protuberance separating said pair of recesses formed therein,and follower means for operatively connecting said pistons to saidoblong inner cam surface, whereby said arcuate pistons are urgedoutwardly to travel along said oblong inner cam surface and impartrotation to said rotor by combustion in said arcuate combustion chambersto provide the power stroke and are urged inwardly by travel along saidinner cam surface to provide the compression stroke.
 32. A rotary engineas described in claim 31 and wherein the head of each of said pluralityof arcuate pistons is formed in mating configuration with the inner endof the associated combustion chamber.
 33. A rotary engine as describedin claim 32 in which said rotor is formed of aluminum.
 34. A rotaryengine as described in claim 33 in which said plurality of arcuatepistons are formed of steel.
 35. A rotary engine for two-cycle operationcomprising, a housing formed to provide an oblong inner cam surface, arotor carried for relative rotation in said housing, walls in said rotordefining at least one combustion chamber of rectangular cross-sectionopening to the periphery of said rotor and extending into said rotoralong an arcuate path having as its center of curvature a point on saidrotor circumferentially spaced from said Combustion chamber, thecenterline of said path extended passing through the axis of said rotor,a correspondingly arcuate piston mounted for curvilinear reciprocationin said combustion chamber inwardly toward the axis of rotation of saidrotor and outwardly toward said cam surface, an arm rigidly secured tothe outer end of said piston and journalled to said rotor for swingingmovement on one axis coinciding with the center of curvature of saidcombustion chamber, and, a cam follower journalled on said arm adjacentto said outer end of said piston in position to track along said camsurface, whereby said arcuate piston is urged outwardly to travel alongsaid oblong inner cam surface and impart rotation to said rotor bycombustion in said arcuate combustion chamber to provide the powerstroke and is urged inwardly by travel along said inner cam surface toprovide the compression stroke.
 36. A rotary engine as described inclaim 35 and wherein a plurality of said combustion chambers are formedin equally circumferentially spaced relation in said rotor, and a pistonand arm and cam follower are provided for each of said combustionchambers.
 37. A rotary engine for two-cycle operation comprising, ahousing formed to provide an oblong inner cam surface, a rotor carriedfor relative rotation in said housing, walls in said rotor defining atleast one arcuate combustion chamber, a correspondingly arcuate pistonmounted for curvilinear reciprocation in said combustion chamberinwardly toward the axis of rotation of said rotor and outwardly towardsaid cam surface, and follower means for operatively connecting saidpiston to said oblong inner cam surface, an intake port formed on oneside of said housing for communicating with said arcuate combustionchamber, an exhaust port formed on the opposite side of said housingpositioned slightly askew from said intake port for communicating withsaid combustion chamber to thereby improve scavenging in said combustionchamber, said exhaust port being positioned for commencing communicationwith said arcuate combustion chamber prior to the commencement ofcommunication between said arcuate combustion chamber and said intakeport, and, the internal end of said arcuate combustion chamber beingrelieved to provide a pair of recesses with one formed to communicatewith said intake port and the second formed for communication with saidexhaust port and having a protuberance separating said pair of recesses,whereby said arcuate piston is urged outwardly to travel along saidoblong inner cam surface and impart rotation to said rotor by combustionin said arcuate combustion chamber to provide the power stroke and isurged inwardly by travel along said inner cam surface to provide thecompression stroke.
 38. A rotary engine, comprising a housing havingcircumferential and end walls defining an enclosure providing an oblonginner cam surface on its inner periphery, a rotor carried in saidenclosure for rotation relative to said housing, said rotor being formedto provide a combustion chamber having a head end near the axis ofrotation of said rotor and curving along a circular arc from such headend outwardly to the outer periphery of said rotor, a correspondinglyarcuate piston slidably mounted in said combustion chamber forreciprocation therein toward and away from said head end, follower meansfor operatively connecting said piston to said oblong inner cam surface,said housing end walls being parallel, said rotor being slidably mountedbetween said end walls, an intake port formed through one of said endwalls in position for communicating with said combustion chamber atspecific angular positions of said rotor, and an exhaust port formedthrough the other of said end walls in position for communicating withsaid combustion chamber at specific angular positions of said rotor,said intake port being positioned slightly Circumferentially askew fromsaid exhaust port for improving scavenging from said combustion chamber,and, the internal end of said arcuate combustion chamber being relievedto provide a pair of recesses with one formed to communicate with saidintake port and the second formed for communication with said exhaustport, said arcuate combustion chamber having a protuberance separatingsaid pair of recesses, whereby said arcuate piston is urged outwardly totravel along said oblong inner cam surface and impart rotation to saidrotor by combustion in said arcuate combustion chamber to provide thepower stroke and is urged inwardly by travel along said inner camsurface to provide the compression stroke.